// The instruction to be updated is either Sub or MI.
Sub = IsCmpZero ? MI : Sub;
- // Move Movr0Inst to the place right before Sub.
+ // Move Movr0Inst to the appropriate place before Sub.
if (Movr0Inst) {
- Sub->getParent()->remove(Movr0Inst);
- Sub->getParent()->insert(MachineBasicBlock::iterator(Sub), Movr0Inst);
+ // Look backwards until we find a def that doesn't use the current EFLAGS.
+ Def = Sub;
+ MachineBasicBlock::reverse_iterator
+ InsertI = MachineBasicBlock::reverse_iterator(++Def),
+ InsertE = Sub->getParent()->rend();
+ for (; InsertI != InsertE; ++InsertI) {
+ MachineInstr *Instr = &*InsertI;
+ if (!Instr->readsRegister(X86::EFLAGS, TRI) &&
+ Instr->modifiesRegister(X86::EFLAGS, TRI)) {
+ Sub->getParent()->remove(Movr0Inst);
+ Instr->getParent()->insert(MachineBasicBlock::iterator(Instr),
+ Movr0Inst);
+ break;
+ }
+ }
+ if (InsertI == InsertE)
+ return false;
}
// Make sure Sub instruction defines EFLAGS and mark the def live.
--- /dev/null
+; RUN: llc < %s -mtriple=i386-unknown-linux-gnu -mcpu=corei7-avx | FileCheck %s
+
+; CHECK: main:
+; CHECK: pushl %esi
+; CHECK-NEXT: movl $-12, %eax
+; CHECK-NEXT: movl $-1, %edx
+; CHECK-NEXT: testb $1, 8(%esp)
+; CHECK-NEXT: cmovel %edx, %eax
+; CHECK-NEXT: xorl %ecx, %ecx
+; CHECK-NEXT: movl %eax, %esi
+; CHECK-NEXT: addl $-1, %esi
+; CHECK-NEXT: movl $-1, %esi
+; CHECK-NEXT: adcl $-1, %esi
+; CHECK-NEXT: cmovsl %ecx, %eax
+; CHECK-NEXT: cmovsl %ecx, %edx
+; CHECK-NEXT: popl %esi
+define i64 @main(i1 %tobool1) nounwind {
+entry:
+ %0 = zext i1 %tobool1 to i32
+ %. = xor i32 %0, 1
+ %.21 = select i1 %tobool1, i32 -12, i32 -1
+ %conv = sext i32 %.21 to i64
+ %1 = add i64 %conv, -1
+ %cmp10 = icmp slt i64 %1, 0
+ %sub17 = select i1 %cmp10, i64 0, i64 %conv
+ ret i64 %sub17
+}